Method and apparatus for the treatment of cotton fibres

ABSTRACT

.Iadd.A method and apparatus for the production of cotton yarns by the cotton system treats cotton fibers in a sequence of steps comprising carding the fibers and forming them into a thin carded web, passing the web through crushing rollers to crush small impurities in the web, subjecting the web on leaving the crushing rollers to a longitudinal drafting action sufficient to cause relative longitudinal fiber movement therein, condensing the web into a sliver, and drafting and spinning and fibers of said silver into yarn..Iaddend.

In the production of cotton yarns.[., a.]. .Iadd.by the cotton systemcotton fibres are carded by means of a cotton carding machine, which maybe either a single cylinder cotton card or equivalently a tandem cottoncard. After carding is finished the fibres are stripped from the card inthe form of a thin carded web, which is then condensed into a roundfibrous mass called a sliver. Without further carding the.Iaddend.sliver of cotton fibres is .Iadd.thereafter .Iaddend.draftedand spun.[., and.].. I have found that this process will be facilitatedand the product improved if the surface of the cotton fibres issmoothed. If this is done, then the fibres will slide over one anothermore readily and fewer neps will be formed during drafting and spinning.

The present invention is designed to provide a method of and means fortreating cotton fibres so as to facilitate drafting and spinning.

According to this invention, .[.a.]. .Iadd.the .Iaddend.very thin.Iadd.carded .Iaddend.web of cotton fibres is ironed to cause all or asubstantial proportion of the individual fibres to be smoothed bypassing it through ironing rollers and the web leaving the ironingrollers is subjected to a drafting action.

In addition to the smoothing of the fibres, the effect of the ironingprocess, if the pressure is adequate, is to crush small impurities suchas particles of cotton seeds and leaves present in the web, and thisassists in the subsequent removal of the impurities. The drafting actionis necessary .[.for two purposes. One of these is that.]. .Iadd.because.Iaddend.unless some tension is applied to the web leaving the nip ofthe ironing rollers, the web will tend to stick to these rollers. Thissticking of the web to the rollers is itself due to two causes, onebeing the presence of resinous oil in some of the impurities whichcontaminate the roller surface, and the other being the staticelectricity generated in the cotton web by its processing prior to andduring the ironing action.

.[.The other.]. .Iadd.Another .Iaddend.purpose of the drafting of theironed web is to .[.bring.]. .Iadd.aid in bringing .Iaddend.about whatmight be called an unexpected effect, since it appears that the actionof moving the fibres relative to one another, as occurs in drafting,sets the substance of crushed impurities free and allows theseimpurities to drop out during subsequent processing (e.g. drafting,spinning, weaving).

The ironing and drafting can most conveniently be effected on the web ofcotton fibres as it leaves the doffer of a carding machine, and beforeit is condensed in width to form a sliver for transfer to a subsequentoperation, e.g. spinning. Consequently, a pair of highly polishedironing rollers may be rotatably mounted on the carding machine frame toreceive the carded web of fibres as the latter is removed from thedoffer, usually by means of a fly comb. These ironing, or impuritycrushing, rollers are driven at a speed sufficient to take up slackbetween the doffer and the ironing rollers. The rollers are thereforedisposed between the doffer and the drawing-off or so called "calender"rollers so that the web, after passing through the nip between theironing rollers, is reduced in width or condensed in the usual manner asit approaches the drawing off rollers which deliver the cotton fibres inthe form of a sliver which is then collected in a can for transfer to asucceeding operation in the course of yarn manufacture. One or both ofthe ironing rollers will be driven, at the same or at a greater surfacespeed than that of the doffer roller so as to maintain the web intension. The surface speed of the drawing off rollers will be greaterthan that of the ironing rollers to produce the drafting effect. Thecalender rollers are rotated at a sufficiently greater surface speedthan the ironing rollers to cause relative longitudinal fiber movementin said web between the ironing rollers and the calender rollers.

The construction and arrangement of apparatus for carrying out theinvention will now be described by way of example only with reference tothe drawings in which:

FIG. 1 is a side view of part of a cotton carding machine modified inaccordance with the invention;

FIG. 2 is a diagram showing an alternative arrangement of ironingrollers, and

FIG. 3 is a diagram showing a further alternative arrangement.

Referring to the arrangement shown in FIG. 1, 10 represents the dofferof a cotton carding machine, 12 is part of the machine frame, 14 is thefly comb used for stripping .Iadd.the .Iaddend.carded web of materialfrom the doffer, and 16 and 18 are the drawing-off or calender rollerswhich deliver the condensed sliver from the machine to a can coiler (notshown). All the parts so far mentioned form well known parts of cottoncarding machines, and need not be described in detail. It will beunderstood that the carding machine has other conventional parts such asa feed lattice, cylinder flats and condenser trumpet which are notdescribed because they form no part of the present invention.

A pair of smoothly ground ironing rollers 24 and 26 are mounted on themachine immediately beyond the fly comb 14, so that the thin carded webof fibres indicated at 28 passes from the fly comb 14 through theironing rollers 24 and 26 to the drawing off rollers 16 and 18. Theironing rollers crush impurities such as seed and fiber fragments in theweb. Ironing rollers .[.16.]. .Iadd.24 .Iaddend.and .[.18.]. .Iadd.26.Iaddend.rotate at a surface speed which is sufficient to take .Iadd.up.Iaddend.slack in the web between them and the doffer, and the calenderrollers are rotated at a surface speed sufficiently higher than theironing rollers to cause relative longitudinal fiber movement in the webbetween the ironing rollers and the calender rollers. The ironingrollers may be pressed together in any convenient manner, for example bymeans of a weighted lever, or by spring pressure, or hydraulic means ora combination of such means.

One manner of loading the ironing roller pass is shown in FIG. 1 whereinthe upper roller .[.26.]. .Iadd.24 .Iaddend.has its shaft .[.27.].journaled in a block 29 slidably guided for vertical movement in astationary support 31 on the machine frame. A spring 33 is compressedbetween block 29 and support 31, and an adjustment at 35 is provided forvarying the compression of spring 33 and therefore the load resulting inthe crushing action on impurities in the web. This arrangement isessentially that of Varga U.S. Pat. No. 2,323,167.

The drive for the ironing rollers may be obtained from any convenientmember of the carding machine, but it is preferred that the drive fromthe doffer roller should be used, so that the ironing rollers will bestarted and stopped simultaneously with the doffer.

For this purpose, in this particular arrangement a gear wheel 30 ismounted on the doffer shaft (not shown), and this gear 30 meshes withintermediate gear wheels 32 and 34, one of which is a disengaging wheelto stop, if required, the apparatus driven by the following wheelassembly.

The wheel 34 meshes with a suitable size change gear 36 mounted on theshaft of the bottom ironing roller 26 and also with a large gear wheel38. The top ironing roller 24 is driven from the bottom ironing rollerthrough coupler gears (not shown) on the opposite side of the machine.

The large gear wheel 38 meshes with an intermediate gear wheel 42 whichin turn meshes with a change gear wheel 44 fixed on the shaft of thebottom drawing-off roller 18. The top drawing off roller 16 is driven bycoupler gears (not shown) on the opposite side of the machine.

A metal guard 46 encloses all the gear wheels in the above describeddrive arrangement. The change speed wheels mentioned above are carriedon adjustable brackets 48 and 50. The reason for the provision of changespeed gearing is so that the most effective speeds for the ironingrollers and the drawing off rollers relatively to the doffer and eachother may be obtained.

As there may be a tendency for some impurities and/or fibres to stick toone or the other of the ironing rollers, means may be provided forkeeping them clear. For example, scraper blades may be pressed intoengagement with the surface of each roller, either by springs or byweighted levers or both. Any other convenient means may be provided forthis purpose.

The ironing rollers may be cylindrical, but it may be desirable to makethem slightly barrel shaped to compensate for deflection when pressedtightly together and so ensure contact along the entire lengths of therollers. Another way of ensuring even distribution of pressure is toarrange the rollers with their axes slightly inclined to one another orcrossed, that is, by swinging one roller about an axis which is radialto both rollers and passes through the mid point of both roller axes,such an arrangement being described in the specification of Pat. No.697,106 (Great Britain).

FIG. 2 shows an alternative arrangement in which instead of employing apair of ironing rollers, two secondary rollers 52 and 54 are spacedapart around the periphery of a main ironing roller 56, so that the web28 passes successively through the nips between the roller 52 and theroller 56, and the roller 54 and the roller 56. It will be understoodthat three or even more secondary rollers could be arranged around amain roller in this way. The arrangements for pressing the secondaryrollers into contact with the main roller, scraping the ironing rollersand ensuring contact along their entire lengths will be similar to thosedescribed with reference to FIG. 1 of the drawings.

Loading units 51 and 53, which are essentially the same as used for.[.leading.]. .Iadd.loading .Iaddend.the ironing rollers of FIG. 1, areprovided to spring load rollers 52 and 54 toward the surface of mainironing roller 56.

FIG. 3 shows diagrammatically an arrangement in which advantage is takenof the facility of web drafting, by providing one or more additionalpairs of ironing rollers so that the web will be treated successively bytwo or more pairs of ironing rollers, each pair of rollers being rotatedat a greater surface speed than the preceding pair whereby drafting willtake place between the successive pairs of rollers.

Rollers 74 and 76 are rotated at a speed sufficient to take up slackbetween them and the doffer 60. Rollers 78 and 80 are rotated at asurface speed sufficiently higher than that of rollers 74 and 76 tocause relative longitudinal fiber movement in the web therebetween, anddraw-off or calender rollers 68, 70 are rotated at a surface speedsufficiently higher than that of rollers 78, 80 to cause relativelongitudinal fiber movement in the web therebetween.

By way of example, as shown in FIG. 3, a power driven gear 81 may beconnected by gears 82 and 83 to rotate ironing roller 76, and by gears84 and 85 to rotate ironing roller 80. Gears 83 and 85 are the samesize, but gear 84 is sufficiently smaller than gear 82 that the ironingroller 80 will be driven at the desired speed higher than ironing roller76.

In FIG. 3, 60 is the doffer, 62 is the fly comb, 64 is the web offibres, 66 is the condenser trumpet, 68 and 70 are the drawing offrollers and 72 is the sliver can. Between the doffer 60 and the trumpet66, there is provided two pairs of ironing rollers 74 and 76, and 78 and80 which are similar to the rollers 24 and 26 in FIG. 1. The drivingarrangement is such that the rollers 78 and 80 rotate at a greatersurface speed than the rollers 74 and 76, but at less surface speed thanthe drawing off rollers 68 and 70. Gear 81 is connected by gearings 86,87, 88, 89 to rotate the calender rollers at the desired speed higherthan ironing rollers 78, 80 as illustrated in FIG. 3. It will beunderstood that to enable drafting to take place the distance betweenthe two pairs of ironing rollers must be greater than the length of thelongest fibres being treated.

In any of the arrangements described, the rollers may be unheated orsome or all of the rollers may be heated by an convenient means, forexample, the rollers may be hollow for passing a heating fluid throughthem, or there may be provided an electrically heated element extendingpartly or wholly through each roller. Furthermore, the rollers of eachpair, or of each set where more than two rollers are used together, mayeither be driven at equal surface speeds or at different surface speedsso as to effect polishing as well as pressing of the cotton fibres.

The rollers may be heated as in Varga U.S. Pat. No. 2,323,167, issuedJune 29, 1943.

In operation, the drawing off rollers 18 and 16, or 68 and 70 mustalways be rotated at a higher surface speed than the ironing rollers (orthe last pair of ironing rollers) to give the drafting effect essentialfor carrying out the method of the invention.

In any of the arrangements described, the ironing rollers may be coatedor plated with a porous layer of metal, preferably chromium, with a verylarge number of capillary size cavities, capable of absorbing andretaining oil, thus ensuring a constant lubrication of the rollersurface. This lubrication will minimize the adhesion of foreign matterto the working surface of the rollers, and will render the working ofthe scraper blades more efficient.

I claim: .[.1. A method of treating cotton fibres comprising the stepsof forming the fibres into a thin carded web, passing said web throughcrushing rollers adapted to crush small impurities in the web andsubjecting said web on leaving said crushing rollers to a longitudinaldrafting action sufficient to cause relative longitudinal fiber movementin the web..]. .[.2. A cotton carding machine having a doffer, a pair ofcalender rollers, a pair of impurity crushing rollers between saiddoffer and said calender rollers adapted to receive a carded web insubstantially full width from the doffer, drive means rotating saidcrushing rollers at a speed sufficient to take up slack in the webbetween the doffer and the crushing rollers, and drive means rotatingsaid calender rollers at a sufficiently greater surface speed than saidcrushing rollers to cause relative longitudinal fiber movement in saidweb between said crushing and calender rollers..]. .[.3. A cottoncarding machine having a doffer, a pair of calender rollers, a pair ofsmoothly ground ironing rollers between said doffer and said calenderrollers adapted to receive a carded web in substantially full width fromthe doffer, load means pressing said ironing rollers together withsufficient force to crush small impurities in said web, drive meansrotating said ironing rollers at a speed sufficient to take up slack inthe web between the doffer and said ironing rollers, and drive meansrotating said calender rollers at a sufficiently greater surface speedthan said ironing rollers to cause relative longitudinal fiber movementin said web between said crushing and calender rollers..]. .[.4. Acotton carding machine having a doffer, a pair of calender rollers, amain ironing roller between said doffer and said calender rollers, aplurality of secondary ironing rollers spaced apart around andcontacting the periphery of said main ironing roller, load meanspressing said secondary ironing rollers toward said main ironing rollerwith sufficient force to crush small impurities in the web, said ironingrollers directly receiving a carded web in substantially full width fromthe doffer, drive means rotating said ironing rollers with sufficientspeed to take up slack in the web between said doffer and said ironingrollers and drive means rotating said calender rollers at a sufficientlygreater surface speed than said ironing rollers to cause relativelongitudinal fiber movement in said web between said ironing andcalender rollers..].
 5. A cotton carding machine having a doffer, a pairof calender rollers, at least two pairs of web impurity crushing ironingrollers spaced along said web between said doffer and said calenderrollers, the first pair of ironing rollers receiving a carded webdirectly from the doffer, drive means rotating each of said pairs ofironing rollers at successively increasing surface speeds with the pairof ironing rolls nearer said doffer being rotated at a speed sufficientto take up slack in the web between it and the doffer and the next pairof ironing rollers being rotated at a speed sufficient to cause relativefiber movement in the web between said pairs of ironing rollers, anddrive means rotating said calender rollers at sufficiently greatersurface speed than the last pair of ironing rollers to cause relativelongitudinal fiber movement in the web between said last pair of ironingrollers and said calender rollers. .Iadd.
 6. In the production of cottonyarns of improved quality and cleanliness by the cotton system, themethod of treating the cotton fibres which comprises, in sequence:a.carding the fibres and forming them into a thin carded web; b. passingsaid web through crushing rollers adapted to crush small impurities inthe web; c. subjecting said web on leaving said crushing rollers to alongitudinal drafting action sufficient to cause relative longitudinalfibre movement therein; d. condensing said web into a sliver; and e.processing the fibres of said sliver into yarn by steps comprisingdrafting and spinning. .Iaddend.